Strollers of this type, also referred to as a push-chair herein, have a chassis whose side frames comprise a handle-bar arm linked in a hinged connection to the front leg and the rear leg, a side sill provided for the seat and hinged between the legs, and optionally a side member which is often coupled to the back of the seat and linked in a hinged connection to the side sill.
Further, strollers of this kind have been widely accepted in the market because of their simplicity and light weight, but they present nevertheless a serious problem arising at the hinged connection of the lower end of the handle-bar arm with the upper end of the front leg. This hinged connection is often carried out with a bracket solid with the leg and to which the handle-bar arm is linked in a hinged connection.
As a result of the weight of the baby and any bags loaded on the stroller, and to sudden movements when pushing the stroller, such as for example when pushing it up or down sidewalks and stairs, the hinged connection is overstressed thus causing at least a partial folding of the side frame of the stroller with the consequent danger thus created for the baby's integrity.